


Demonism

by NotEvenThat



Category: Shadowhunters (TV), The Mortal Instruments Series - Cassandra Clare
Genre: Alec is a good boyfriend, Brief thoughts about consentual noncon, Demonic Magnus, Demonic flu, Dominant Magnus, Fluff and Smut, M/M, Magnus is sick, Powerful Magnus Bane, Self-Conscious Magnus, Weird Body Kinks, slight body horror
Language: English
Status: Completed
Published: 2017-04-27
Updated: 2017-04-27
Packaged: 2018-10-24 16:20:30
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,069
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10745355
Author URL: https://archiveofourown.org/users/NotEvenThat/pseuds/NotEvenThat
Summary: Magnus gets a demonic flu that causes his body to change. Alec, knowing nothing about his boyfriend's sickness, tries to surprise him with soup and is blindsided by Magnus's new form.





	Demonism

When Magnus told Alec that he was sick and that he had to cancel their date, Alec had accepted that he wouldn’t be seeing his boyfriend that night. It was only an hour later, when he had finished all of the paperwork for the missions they’d just been on, that he realized Magnus hadn’t told him not to come over. He told him that he had to cancel their date. Which, was a very different thing, at least in Alec's mind.

Alec hadn’t seen Magnus in three days. They’d both been extremely busy. Magnus was working on a dark spell, that was apparently very finicky and dangerous. He hadn’t told Alec not to go over but he had told him to call before he did, so he didn’t walk into anything bad and hurt himself or Magnus. Alec had called a couple of times but he’d been swamped with paperwork, missions and meeting. He always missed the call when Magnus called him back and Magnus would miss the call when he tried again. They’d finally settled on texting each other whenever they could and that was the extent of their communication for three whole days.

Now, Magnus was sick and Alec was finally left with nothing to do at the Institute. It only made sense that he would stop and get Magnus some of his favorite soup at the Indonesian restaurant that he liked.

The whole walk took less than ten minutes and it only took another ten for Alec to wait for Magnus’s soup. Twenty minutes later, Alec was standing outside of Magnus’s loft, a warm bowl of soup and a cup of tea balanced in one hand as he carefully opened the door. He didn’t knock. Magnus was a light sleeper and if he was asleep, Alec didn’t want to wake him up.  

The loft was dark, only lit by small, orange glowing salt lamps that Magnus had set up near the windows in the living room. Everything was silent, the only sound coming from a few fans. Alec walked in carefully, wishing he had a free hand to activate his sight rune, so he could find Magnus without turning on any of the lights.

A second later, he realized that he didn’t need it. Magnus was curled up on the couch, lit by the orange lights and the moonlight streaming through the windows. At least, Alec _thought_ it was Magnus. The body curled under the blankets was definitely shaped like Magnus. Only, Alec could see Magnus’s face turned towards him and something was deeply wrong with the sight.

Alec crept forward carefully and then stumbled, tripping over the coffee table and cursing quietly, as he scrambled to keep the soup and tea upright. He landed loudly on his knees a few feet away from the couch and then froze, looking up at Magnus, horrified.

For a few moments, nothing happened. Then Magnus’s eyes opened and Alec was instantly comforted by the familiar sight of the glowing eyes before he looked at the rest of Magnus’s body and realized that something _was_ very wrong with his boyfriend.

Magnus’s body was covered in dark shimmering black scales. There were horns, curling off Magnus’s head and his ears came to a sharp points, that looked like they would cut, if Alec tried to touch them. Magnus sat up in front of him and stared at Alec, just as incredibly as Alec was staring at him and then slowly his expression shifted to horror. There was even something.. wrong looking about the way his muscles shifted in his body. He looked like a demon, like a _real_ demon, straight from Edom.

“Are you okay?” Alec blurted out, just as Magnus said, “Alexander!”

Magnus looked horrified. He kept glancing from Alec, to the soup in his hands, down to his own scaled (and clawed, Alec noted as he looked closer) hands and then back up to Alec. “What are you doing here?” He asked fiercely, his eyes finally landing on Alec’s face and staying there.

“You..” Alec swallowed and then opened his mouth and tried again. Magnus seemed more alarmed by Alec’s presence than the state of his body, which hopefully meant that this was normally and Magnus wasn’t in danger. “You said that you were sick and I wasn’t busy, so I thought I would go get you that soup you like.” Alec held up the plastic bowl of soup and the small container of rice that had come with it, “Sayur Sop.” He offered quietly, too stuck by the feeling that he was unwelcome to feel embarrassed by his pronunciation of the Indonesian word.

Magnus didn’t respond for a long moment but his eyes softened and he glanced down at himself again before looking back up at Alec, suddenly seeming much smaller than he had a moment ago. “Thank you..” He said softly, his eyes not quite reaching Alec’s. “You don’t have to stay. I should be back to normal in a couple of days, you can come back then.” Magnus fell silent for a moment and then continued, quietly, “If you even want too.”

It took Alec an embarrassingly long moment to realize that Magnus thought he didn’t want to be around him like this. “Magnus, I.. I don’t mind this. Whatever.. This is.. As long as you’re okay.” The question was obvious in his tone; _You are okay, right?_

Magnus glanced up at him again. His shoulders were sunken in on themselves and his dark arms were wrapped around his waist, as he stared at Alec hesitantly, like he was expecting Alec to throw the soup in his face or run out of the room. He had never seen Magnus so small and it broke his heart. “Yeah.. It ah.” Magnus was obviously uncomfortable talking about it and Alec was seconds away from cutting in and telling Magnus that they could just ignore it, if he wanted, when he started talking again. “It’s from the spell I was working on. I was using a lot of dark magic and sometimes this happens… It's like a flu. It’ll go away, eventually.”

“Alright.” Alec sat awkwardly for a moment before shifting on his numb legs and settling down on the couch, next to Magnus, pressing the food into his hands. “It's probably cold by now..” It had been almost a half an hour since Alec had bought the soup. It was probably cold and gooey. “I can warm it up for you, If you want...” Alec thought for a moment that Magnus could warm it up himself, if he really wanted too, but then he glanced across Magnus’s body and realized that he wasn’t sure if he could do magic like this and there was no way he was going to ask, not after seeing how uncomfortable Magnus had been moments ago. 

“It’s fine, Alexander.” Magnus pressed a little bit closer to Alec’s side and then relaxed into him, when Alec didn’t push him away. They sat there for a while, Alec gently rubbing the hard scales on Magnus’s shoulder as he ate. It was weird. He was so use to the soft skin on his boyfriend's body, so distinctly different than his own rough, calloused body. He could imagine how it would feel if Magnus was over him. Alec’s eyes flickered to Magnus’s hands and he watched the sharp claws lift the spoon. He could imagine Magnus, running his claws down Alec’s body, pressing in just enough to leave trailing red marks but not enough to break skin. He wondered if Magnus’s lips would feel different like this. If they were hard like his skin or if they were still soft. He wondered if his cock was..

Alec shifted in his seat. He realized all too suddenly that he was aroused and it was going to be obvious, if Magnus glanced over at him. He looked down casually, trying to see if his half hard cock was showing through his pants and then let out a harsh breath when he saw that it was.

Why was he even aroused by this? His boyfriend was sick. He probably didn't feel good and Alec was sitting there getting turned on by his body. That was like Magnus getting aroused by Alec coughing or throwing up. It was weird, it was sadistic. Magnus deserved to relax until he felt better and Alec was sitting next to him, trying not to imagine how good his cock would feel with scales on it.

Magnus’s shifted away from Alec and his voice cut through the haze of arousal and self deprecation in his mind. “If I’m freaking you out, you can leave.” He stared up at Alec solemnly, like he had just accepted that Alec was grossed out by the state of his body and that was it. “I understand.. Really, you don’t have to feel bad. You’re sweet, you brought me soup but you don’t have to force yourself to stay.”

Alec blinked and then he blinked again. Then, as Magnus words sunk in, he twisted around and looked at the wall, so that Magnus wouldn’t see his cheeks blushing red. “That's not.. Why I was.. staring.” Staring, squirming, trying not to push his hand into the bulge in his pants.

Neither of them spoke for a moment and then Magnus let out a soft, _‘oh’._ Alec was sure that he had spotted Alec’s cock and the thought made him want to stand up and leave or hide under the blankets. This wasn’t like the other things they’d explored. This wasn’t a normal kink, that he was embarrassed by. This was weird. Magnus was _sick_ and he was officially the worst, most inconsiderate boyfriend in the world.

Magnus let out of a soft chuckled and when Alec turned, he was staring at him with a soft, amused expression. The relief that Alec felt, seeing Magnus expression, was short lived when he opened his mouth. “Is there a reason I turn you on like this?”

“Magnus.” Alec squirmed and looked at Magnus displeased, which only made his boyfriend smile wider.

“What? I’m just curious. I think I deserve to know which aspect of this is making you hard.” Magnus leaned forward and place the food down on the table before turning back to Alec and moving himself onto his lap in one solid, fluid movement. “Would it help if I promise to let you see the rest, if you tell me?” Magnus asked softly in his ear, only hand moving to pull the collar of the cotton shirt he was wearing down. His dark scaled chest shimmered in front of Alec and he whined, his fingers twitching to touch it, even knowing that Magnus wasn’t going to let him, until he gave him an explanation.

“I just..” Magnus pressed his lips gently against the side of Alec’s neck, right against the deflect rune and Alec shuttered, tightening his hands on Magnus’s hips before continuing. “You just look so powerful.” Alec whined out and Magnus sat up and stared at him in surprise. “You’re so powerful, Magnus. _God,_ I had to go jack off in the bathroom after that fight you had with Iris.” The words were pouring out of Alec mouth and he was too aroused to even care that most of what he was saying was horribly embarrassing. “You could do whatever you wanted to me and I’d be so powerless.” He would be too. Magnus could control every one of his movement, he could probably even control his thoughts, if he wanted too. He knew Magnus would never do that without permission but the thought made Alec want to beg for it. He couldn’t count the number of times he’d laid in bed at home, touching himself to the thought of Magnus taking everything he wanted from him. “And now you look like it. You.. You always look powerful but you just- You look so _otherworldly._ People always underestimate you and it's like you look as powerful as you are right now.” Alec finished breathlessly as he stared up at Magnus, his expression so utterly honest.

Magnus watched for a brief moment before grinning and leaning in to press Alec back against the couch. “I’m going to fuck the hell out of you.” Magnus growled deep in his ear and Alec clenched his eyes shut, trying hard not to cum right there. 

**Author's Note:**

> Insert a shrug emoji.  
> I've always wanted to write something where Magnus's demonic side comes out and hey, I did it today, when I have a million other things I should be doing! Leave a comment, if you feel so inspired too.


End file.
